/Engine/Source/Editor/UnrealEd/Public/GraphEditor.h
typedef TBaseDelegate_TwoParams< [FReply](API\Runtime\SlateCore\Input\FReply), const [FGeometry](API\Runtime\SlateCore\Layout\FGeometry) &, const [FPointerEvent](API\Runtime\SlateCore\Input\FPointerEvent) & > FOnMouseButtonDown